Die casting machines generally utilize one of two classifications of casting material pumping systems, either a hot chamber system or a cold chamber system. Hot material chamber die casting machines include parts that are partially submerged in a vat containing the molten metal and thus operate at the temperature of the metal bath. Cold chamber die casting machines are unheated except for the die member which receives the molten metal during the casting process. Hot chamber systems are used primarily for the casting of metals having low melting points such as tin, zinc and lead alloys. Cold chamber machines can be used for die casting most metals, however, they are most commonly used for aluminum, magnesium and copper alloys.
The industry has lavished great care in choosing materials for the construction of hot chamber die casting machines. Improved materials for the various parts have led to enhanced resistance against wear, hardening and softening. The industry, however, has had little success in overcoming failure problems resulting from the high operating pressures present in the hot melt die casting process.
A recent, major improvement in the industry has been a reinforced casting. Specifically, the improvement is a reinforced gooseneck and reinforced components for use with a hot chamber die casting machine. The improvement provides for the reinforcement of the gooseneck, nozzle, and nozzle seat. The preferred embodiment focuses on reinforcing the gooseneck as this is the location where most pressure-caused failures occur. See U.S. Pat. No. 6,481,489 issued to Melvin A. Jones which is herein incorporated by reference.
Another problem has been communication between the pressure cylinder of the gooseneck and the molten metal reservoir. Various attempts have been made to fast fill the chamber of the gooseneck or to more completely reach the bottom of the reservoir of molten material. U.S. Pat. No. 4,261,414 discloses a complicated mechanism for rapidly providing molten metal to a die casting machines. This patent discloses a double toggle arrangement including a bell crank pivotally mounted on a yoke. The patent also discloses a double shaft arrangement for filling the chamber of the gooseneck. Shaft 104 operates gate valve 100. Gate valve 100 has two apertures. Aperture 112 provides communication between pump chamber 96 and pot 32. Aperture 114 provides communication between chamber 96 and nozzle 54. Shaft 108 operates pump 110 mounted in chamber 96. Movement of shafts 104 and 108 operate in sync to fill and drain chamber 96 through apertures 112 and 114. Obviously, keeping the shafts in sync would be difficult. While this system may function, it cannot be retrofitted to an existing gooseneck assembly. Maintenance also would be difficult.